What Mukilteo Homes Need From a Replacement Window
Local risk and climate data for Mukilteo, WA are below, translated into plain terms for a window buyer rather than left as raw codes. Use it to check a proposed spec before you sign, not just to browse.
Licenses checked · Washington State Department of Labor & Industries
4CIECC climate zone · ENERGY STAR Northern zone
Mukilteo's climate zone, in plain terms
Mukilteo falls in IECC climate zone 4C, and ENERGY STAR separately groups Snohomish County into its Northern zone for window certification.
Those two numbers, not the brand on the box, set the U-factor and SHGC worth checking on any quote you get in Mukilteo.
A Seattle-Tacoma-Bellevue, WA contractor who can't name either one on request is worth a second question before you sign.
Data: U.S. EPA / DOE, ENERGY STAR, ENERGY STAR Version 7.0 Climate Zones by County/ZIP (Windows, Doors, and Skylights) (V7.0); Pacific Northwest National Laboratory (DOE Building America), Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates (PNNL-33270) (2021 IECC), from the nearest NOAA station 1.4 mi away.
What FEMA's risk data says about Mukilteo
Neither rating changes a window's energy label, but both are exactly what impact-resistance and design-pressure ratings are built to answer for a Mukilteo home.
Ask specifically about design pressure and impact rating for Mukilteo, not just energy performance, if either risk rating comes back on the high side.
- Strong wind
- Very Low
- Winter weather
- Relatively High
Data: FEMA, National Risk Index for Natural Hazards - County-level table, v1.20 (v1.20, December 2025).
Guides to finish before Mukilteo window bids come in
- How to Read an NFRC Window Label Four numbers on one sticker decide most of a window's real-world performance. Here's what each one means.
- ENERGY STAR Window Criteria by Climate Zone ENERGY STAR splits the country into four zones, each with its own numbers. Here they are, and why the Northern zone works backward from the other three.
- Impact Windows vs. Shutters in Florida's Hurricane Zones Florida gives homeowners two paths to a protected opening. Here's how each one is tested, and where the HVHZ raises the bar further.
Mukilteo's longest-licensed window installers
Oldest license first, newest last, pulled directly from the state's file. This list isn't for sale.
- Superior Glass Installatns INCVerify license
- Cascade Window & Glass INCVerify license
- Ace Glass LLCVerify license